Process for the production of ortho-substituted phenols



Unitcd States Patent 3,290,389 PROCESS FOR THE PRODUCTION OF ORTHO- SUBSTITUTED PHENOLS Willi Hahn, Cologne-Stammheim, Germany, asslgnor to Farbenf'abriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Jan. 18, 1962, Ser. No. 167,169 Claims priority, application Germany, Jan. 25, 1961,

F 33,054 Claims. (Cl. 260-619) The present invention relates to a process for the production of alkylated phenols, and more particularly to the production of phenols which are alkylated in the ortho-position to the hydroxyl group, from phenols and olefins using aluminum oxide catalysts.

It is known that alkylphenols may be prepared generally by reacting phenols with olefins in the presence of catalysts. The catalysts mainly used for this purpose are acid in nature, such as sulphuric acid, hydrochloric acid, phosphoric acid, salts which are acid in reaction, fullers earth activated by acids, and the like. Lewis acids (such as aluminum chloride and boron fluoride) may also be used. All these catalysts, however, have the disadvantage that they are strongly corrosive, so that they require reaction vessels made of special materials. In addition, they generally lead to the formation of mixtures of various alkylation products. The removal of the catalysts from the reaction mixture often gives rise to considerable difficulties.

In German Patent No. 944,014, it has been proposed to use metal phenolate (phenate) catalysts for alkylation at the nucleus. Although these metal phenolate catalysts have only a feeble corroding action, the removal of the catalyst from the alkylated mixture still gives rise to considearble difficulties, particularly because it is necessary in the catalyst removal to avoid using acids for splitting the metal phenolates, owing to their isomerizing action on the reaction products.

It has been disclosed further in British Patent No. 325,855 that orthoand para-cresol may be reacted with propylene in the presence of catalysts which have the effect of splitting off Water, to form a mixture of various isopropyl derivatives. In this process, using an aluminum oxide catalyst which has been pressed until only moist and then dried, three isomers each alkylated once in the nucleus are obtained in the gaseous phase as reaction products of ortho-cresol and propylene. In these isomers, the propyl radicals have entered the nucleus in the ortho-metaand para-positions to the hydroxyl group of the cresol, and the isomers so-produced cannot be isolated from one another in pure form by fractional distillation. Dipropylated cresols are formed in addition to the abovenoted monoalkylated isomers. The course of the reaction is, therefore, very non-uniform in the gaseous phase i.e. with respect to the selective production of a particular isomer.

On the other hand, it has been disclosed in US. Patent No. 2,430,190 (especially Examples 1 and 2), that phenol does not react with propylene in the presence of aluminum oxide in the temperature range of 150 to 200 degrees C. in the liquid phase. Reaction occurs only after the addition of halogen compounds, for example hydrogen chloride or isopropyl chloride, but the reaction consists predominantly of etherification at the oxygen atom of the hydroxy group.

It is an object of the present invention to overcome the foregoing drawbacks and to provide a process for selective ortho-alkylation of phenols with olefins in the presence of gamma-aluminum oxide as catalyst.

Other and further objects of the invention will become apparent from the within specification and accompanying examples.

It has been found in accordance with the present invention that ortho-alkylphenols may be produced in a simple manner and in good yields and with a uniform reaction by treating phenols with olefins in the presence of a catalyst, if gamma-aluminum oxide is used as catalyst and the reaction is carried out in the liquid phase.

In view of the prior art, it was by no means to be expected and therefore extremely surprising to find that ortho-alkylphenols may be obtained in good yields from phenols and olefins in the liquid phase in the specific presence of gamma-aluminum oxide catalysts. Significantly, on the other hand, other aluminum oxides are not suitable.

Olefins suitable for the process in accordance with the invention are generally unsaturated compounds of the aliphatic, alicyclic, or araliphatic series with olefinic double bonds. Typical representatives are those compounds containing ethylenic unsaturation, such as ethylene, propylene, butylene, pentene, hexene, cyclopentene, cyclohexene and styrene. It is particularly advantageous to use lower olefins, such as those occurring in modern catalytic cracking processes, e.g. ethylene, propylene, and the isomeric butenes, such as 1- or Z-butene.

The catalysts which are effective in the process of the invention are aluminum oxides consisting entirely or mainly of gamma-aluminum oxide. These catalysts are obtained by precipitating hydrates of aluminum oxide from aqueous salt solutions by methods known per se, for example by treating an aluminum nitrate solution with ammonia (see Germany Patent No. 449,730) or a sodium aluminate solution with nitric acid, and heating the gels obtained after drying to temperatures ranging between 400 and 1000 degrees C., especially 450 and 700 degrees C. Heating the aluminum oxides to the said temperature range is an essential preliminary treatment, because it is necessary for activating the aluminum oxide so that it will catalyze the ortho-alkylation of the phenols in accordance with the process of the invention, and for producing the gamma-form of the aluminum oxide. The heat treatment may be carried out either in a current of air or in a current of inert gas such as nitrogen and should last generally about 1 to 10 hours.

The fact that catalytic activity for the ortho-alkylation is a specific property of gamma-aluminum oxide, which other compounds capable of splitting off water do not possess, is shown from the behavior of mixed catalysts composed of aluminum oxide and silicon dioxide. Whereas mixed catalysts of the latter type (containing for example 5 to 6% SiO and pretreated in the same manner as aluminum oxide) give only very low phenol yields, the catalysts used in technical cracking processes (which contain about to SiO give rise to mixtures of various isomeric alkyl phenols in which the ortho-compounds are present only in relatively small proportions.

The aluminum oxide catalysts may be used either in the form of coarse particles or as fine powders. Granular materials are suitable particularly as solid bed catalysts, whereas powdered catalysts are preferably used for discontinuous or batch processes, or where the reaction is carried out in a liquid fluidized bed.

The optimum temperature for carrying out the alkylation depends on the individual olefins. In general, temperature ranges of 200 to 400 degrees C., and especially 250 to 350 degrees C. will be used, but lower and even higher temperatures may also be employed.

The pressure in the reaction vessel may be varied within wide limits. It is advantageous to operate under a pressure which is greater than the total pressure of the re- 3 action components at the particular temperature. Pressures between and 500 atmospheres, preferably be tween 30 and 200 atmospheres, above atmospheric pressure will generally be suitable.

4 mixture with their position isomers by random alkylation of phenols, and they could only be isolated in pure form from this mixture only by complicated and expensive methods. The catalysts used in accordance with ing out the continuous process, the reaction components may be passed over the catalyst arran fixed bed.

It will be appreciated that phenols selectively alkylated in the ortho-position to the hydroxyl group are obtained by the process according to the invention. Heretofore,

In the process according to the invention, the phenol 5 the process of the invention, on the other hand, are so which is to be alkylated is placed in a suitable pressure specifically ortho-directing that the resulting ortho-alkylvessel, the aluminum oxide catalyst is added, and the phenols are practically free from other position isomers, olefinic components are then added under pressure at and in many cases they may be utilized technically or put elevated temperatures. To ensure thorough mixing of into further processes directly after removal of unreacted the gas and liquid, as well as to effect uniform distribu- 1O phenols, without further purification. tion of the catalyst in the reaction mixture, it is advan- The process of the invention has decided advantages tageous to shake or stir the contents of the autoclave by over the process of the aforementioned German Patent suitable agitation means. No. 944,014, in which ortho-alkylphenols may also be ob- The ratio of olefin to phenol will vary from case to tained. Firstly, the continuous alkylation with a solid case. It depends mainly on the reaction product desired bed aluminum oxide catalyst is technically much easier and on the degree of conversion sought. If only one to carry out than, for example, alkylation using a phenolalkyl radical is to be introduced into the phenol nucleus aluminum phenolate suspension, which is sensitive to air in ortho-position to the hydroxyl group, approximately and moisture and which, moreover, has an undesirable equimolar quantities of phenols and olefins will be used. tendency to crystallize, Removal of the catalyst in the Phenols substituted in both ortho-positions may be proprocess according to the invention, if suspended in the duced by using excess olefin. In that case, it will be reaction mixture, is effected by simple filtration at the advantageous to use 2 to 3 mols of olefin per mol of end of a discontinuous operation, or may be completely phenol. omitted when working with a solid bed catalyst, whereas The quantity of catalyst to be used depends on the in the case of the reaction products obtained by the procform in which it is applied and on the manner in which ess of said German Patent No. 944,014, the metal phenothe process of the invention is carried out. In a disconla mu be decomposed y treatment with aqueous media tinuous or batch method, 0.1 to by weight of alumiand subsequently separated. num oxide, calculated on the phenol to be alkylated, will An essential advantage of the process of the invention generally be used. It is particularly advantageous to is due to the fact that mono-o-alkylphenols may be obuse 0.5 to 10%. More specifically, the ratio of catalyst 30 tained in excellent yields without the formation of large to phenol by weight may be broadly stated as 0.0010.3 l, quantities Of 2,6-dialkylphenols, by merely adjusting the and more preferably a 0.005 0'1:1, I th ti uou molar ratio of phenol to olefin so as to favor mono alkylamethod, O.150, and preferably 1 to 25 parts by weight tion. This is shown in the Table I, which gives the yields of the starting reaction mixture per part by weight of Of P PY P obtainable ffOm phenol and P fixed bed catalyst will be converted in one hour. Genpy n f r VaTiOllS phenol conv rsi ns by each Of the erally, one part by weight of phenol may be converted two processes when carried out under the optimum con- 7 per hour in the continuous method where the catalyst ditions for mono-alkylationis present in the broad range of 002-10 parts by weight The ollho-alkylphenols easily Obtained y the Process per part per hour of phenol passed th th h, d of the invention are known and are valuable antoxidants or particularly th ti may b 04 1;1 per h and stabilizers. They may be used also as intermediate of catalyst to phenol. Stated another way, the phenol Products for the PTBparatiOll of Compounds these P may be passed per hour through the fixed bed catalyst and for the Prfiparation 0f emulsifiers, IaW at a ratio of 0.1-5021 and more particularly 125:1 parts tenals for detergents: insecticides and dyestuffsbyTvi leighliplhenohcategyst f0; tgtal conversion.1 45 EXAMPLE 1 e a ya e may I e wor e up in a simpe manner I by filtering off the catalyst, which may be used again i fi g g o g gg g aiih ii) p ri s lig vi gig l r t x: is:tzztfziaizmtuiztttisrzstutira s? tense e lation crystallization etc In; b 1 r obtained by precipitatlng an aqueous aluminum nitrate Y e'used 1f q solutlon with ammonia (see Z. :anorg. Chemie 188, 378

The process may be carried Out 1n batches r c lnu- (1930)), drying the salt-free hydrate of the oxide at 150 ously as the artisan will appreciate. In the continuous degree C., and then heating in a current of air at 450 operation, the catalyst (in a finely divided form) together degrees C. for 5 hours. Then, 84 parts by Weight of liquid with the phenol is pumped through the reactor and olefin r propylene are pumped into this mixture of phenol and 1s added at the same time. In another method of carrycatalyst.

bowi it 328 5238 18 lat 5% $2 5% 'y-AlgO 5. 3 280 30-15 175 1:1 67 96 4 -Auo 5. 3 280 95-20 188 1 :2 86 82 15 The contents of the autoclave are stirred for 3 :hours at ged in a Solid or 280 to 300 degrees C., the pressure in the reaction vessel falling from 198 to 22 atmospheres above atmospheric pressure (atmospheres gage). After cooling, the pressure is released from the autoclave and the catalyst is filthese ortho-alkylphenols could only be obtained in a tered from the liquid reaction product (265 parts by weight). Gas chromatographic analysis shows the reaction product to have the following composition:

Percent Phenol 21.8

2-isopropylpheno1 63.3 2,6-diisopropylphenol 12.1 Other diisopropyl phenols 2.5 2,4,6-triisopropylphenoi 0.3

metaand para-isopropylphenols could not be detected.

EXAMPLE 2 6 EXAMPLE 5 Using the same process as in Example 1 and the same aluminium oxide catalyst, 188 parts by weight of phenol are reacted with 166 parts by weight of propylene in the presence of 10 parts by weight of catalyst at a temperature of 293-300 C. The pressure is raised to 150 atm. and falls to 20 atm. at the end of the reaction. After 3 hours, 320 parts by weight of reaction product, liquid at room temperature, are obtained; the product has the following composition:

Percent Phenol 4.1

o-Isopropylphenol 45.4 2,6-diisopropylphenol 42.0 Other diisopropylphenols 2.9 2,4,6-triisopropylphenol 4.8

EXAMPLE 6 188 parts by weight of phenol and 10 parts by weight of the aluminium oxide described in Example 1 are heated to 280 degrees C. in an autoclave with stirrer, and 164 parts by weight of cyclohexene are pumped into the mixture. The pressure is initially atm. and falls to 23 atm. during the reaction. After stirring for 4 hours at Table II Y M f Composition of the liquid reaction product in percent by weight 1e 0 Pretreatment of liquid reaction Pressure all Other 2,4,6-

the A120 product in initial pressure Isopropyl phenol diisopropyl triisopropylgms. 220 atm. Phenol Isopropyl- 2,6 diisophenols phenol phenyl-ether propyl- 0- mand pphenol 3 /250280 C 302 79. 5 13. 8 2 I450 O 397 168 21.8 62.9 i /700 C 399 210 35.9 50. 5 (i /1000 0-. 323 120 66. 7 26. 7 5 /1300 C 307 37 81. 1 18. 3

=h0urs.

EXAMPLE 3 300 degrees C., the mixture is cooled to room tempera- Commercial -aluminum oxide, formed into pellets of 5 mm. diameter and activated by heating to 450 to 500 degrees C. in a current of air, is arranged as a solid catalyst bed in two cylindrical pressure vessels arranged in series connection one behindthe other. Phenol and technical n-butene are pumped in a ratio by weight of 3 :2 into the first reactor with the aid of two liquid dosing pumps. The product is removed continuously from the second reaction vessel by releasing pressure through a valve in such an amount that a pressure of to atmospheres is established in the reaction chamber. With a throughput of 3 parts by weight of starting product per part by Weight of catalyst per hour, 97 to 99% of the butene is converted. The reaction product has the following composition:

Percent Phenol 22.0 o-Sec.-butylphenol 60.2 mand pSec.-butylphonol Sec.butyl-phenyl ether 2,6-di-sec.butylphenol and 11.6 Other dibutylphenols 4.6

EXAMPLE 4 Using the same apparatus and catalyst as in Example 3, phenol and ethylene in a ratio of 1:3 are reacted at 300 degrees C. and 100 atmospheres pressure.

Using a throughput speed of 0.9 part by weight of phenol per part by weight of catalyst per hour, an alkylate is obtained which a fractional distillation yields 38% phenol, 47% o-ethylphenol (B.P. at 50 mm. Hg degrees C.) and 15% 2,6-diethylphenol (B.P. at 50 mm. Hg 138 C.).

ture and the catalyst is removed by filtration. The filtrate (320 parts by weight) is fractionally distilled. 54 parts by weight of cyclohexene (B.P. at 760 mm. Hg 81 C.), 81 parts by weight of phenol (B.P. at 10 mm. Hg 72 C.) and 170 parts by weight o-cyclohexylphenol (B.P. at 10 mm. Hg 148 C., M.P. 57 C.) are thereby obtained.

' EXAMPLE 7 752 parts by weight of phenol and 40 parts by weight of powdered aluminum oxide described in Example 1 are heated to 270 C. in an autoclave with a magnetically operated stirring device, and 450 parts by weight of technical n-butene is pumped in in the course of one hour by means of a liquid dosing pump. In the process, the temperature is gradually raised to 300 C., and stirring is then continued for a further two hours at 300 C. The pressure is initially 78 atm. and falls to 20 atm. during the reaction. After the autoclave has cooled to 20 C. and the pressure has been released and the catalyst has been filtered off, 1040 parts by weight of liquid reaction product of the following composition remain:

Percent Phenol 14.3 o-Sec. butylphenol 79.3 2,6-di-sec. butylphenol 2.2 2,4-di-sec.-butylphenol+tri-sec.-butylphenol 1.7

EXAMPLE 8 The procedure of Example 6 is repeated but in this case the cyclohexene is replaced by styrene. Similar results are achieved whereby ortho-pl1enyl-ethyl-phenol of the boiling point 135 C. at 0.5 mm. pressure is obtained.

What is claimed is:

1. Process for the production of phenols alkylated in ortho-position to the hydroxyl group which comprises reacting phenol and an olefin in liquid phase in the presence of gamma-aluminum oxide as catalyst, and recovering the reaction product.

2. Process according to claim 1 wherein the reaction is carried out at a temperature between about 200-400 C. and a pressure between about 5500 atmospheres gage, the phenol and olefin being present in equimolar amounts whereby mono-ortho-alkyl phenol is obtained.

3. Process according to claim 1 wherein the reaction is carried out at a temperature between about 200400 C. and a pressure between about 5500 atmospheres gage, a molar excess of olefin being used whereby phenols alkyl-substituted in both ortho positions are obtained.

4. Process according to claim 1 wherein said process is a batch process and between about 0.1 and 30% by weight of the aluminum oxide based on the phenol used is present.

5. Process according to claim 1 wherein the process is carried out continuously with the catalyst in the form of a fixed bed and with the phenol and olefin continuously being passed therethrough and wherein the catalyst is used in an amount of parts by weight per part by weight of phenol per hour of from 002-10: 1.

6. Process according to claim 1 wherein the catalyst is suspended in the reactants and the alkylated phenol is separated therefrom by filtration and isolated by fractionation.

7. Process for producing mono-ortho-alkylated phenol which comprises contacting phenol and a hydrocarbon having mono-ethylenic unsaturation selected from the group consisting of ethylene, propylene, butylene, pentene, hexene, cyclopentene, cyclohexene and styrene in equimolar amounts in the presence of gamma-aluminium oxide as catalyst in a weight ratio to phenol of 0.001- 0.3:1 in a batch process at an elevated temperature and a pressure at which the reaction proceeds in the liquid phase at the particular temperature, and recovering the mono-ortho-alkylated phenol thereby formed.

8. Process for producing mono-ortho-alkylated phenol which comprises contacting phenol and a hydrocarbon having mono-ethylenic unsaturation selected from the group consisting of ethylene, propylene, butylene, pentene, hexene, cyclopentene, cyclohexene and styrene in equimolar amounts in the presence of gamma-aluminum oxide as catalyst in a weight ratio to phenol of 002-1021 per hour in a continuous process at an elevated temperature and a pressure at which the reaction proceeds in the liquid phase at the particular temperature, and recovering the mono-ortho-alkylated phenol thereby formed.

9. Process for producing di-ortho-alkylated phenol which comprises contacting phenol with a molar excess of a hydrocarbon having mono-ethylenic unsaturation selected from the group consisting of ethylene, propylene, butylene, pentene, hexene, cyclopentene, cyclohexene and styrene in the presence of gamma-aluminium oxide as catalyst in a weight ratio to phenol of 0.0010.3:1 in a batch process at an elevated temperature and a pressure at which the reaction proceeds in the liquid phase at the particular temperature, and recovering the 2,6-dialkylated phenol thereby formed.

10. Process for producing di-ortho-alkylated phenol which comprises contacting phenol with a molar excess of a hydrocarbon having mono-ethylenic unsaturation selected from the group consisting of ethylene, propylene, butylene, pentene, hexene, cyclopentene, cyclohexene and styrene in the presence of gamma-aluminum oxide as catalyst in a weight ratio to phenol of 0.0210:1 per hour in a continuous process at an elevated temperature and a pressure at which the reaction proceeds in the liquid phase at the particular temperature, and recovering the 2,6-dialkylated phenol thereby formed.

References Cited by the Examiner UNITED STATES PATENTS 2,125,310 8/1938 Perkins 260-624 2,360,814 10/1944 Mattox 260-671 X 2,448,942 9/1948 Winkler et al. 260-621 2,450,766 10/1948 Nixon et a1. 260624 2,678,951 5/1954 Smith et al. 260621 OTHER REFERENCES Ipatieff: Catalytic Reactions at High Temperatures and Pressures, pp. 664-668 (5 pages), pub. by the Macmillan Co., New York (1936).

Newsome, I. W.: Aluminum Properties, Alcoa, Pennsylvania (1960), No. 10.

LEON ZI TVER, Primary Examiner.

H. G. MOORE, D. M. HELPER, Assistant Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,290,389 December 6, 1966 Willi Hahn It is hereby, certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 32, for "0.005-0121" read 0.005-0.l:1 column 5, line 60, for "butylphonol" read butylphenol Signed and sealed this 19th day of September 1967.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER Attesfing Officer 

1. PROCESS FOR THE PRODUCTION OF PHENOLS ALKYLATED IN ORTHO-POSITION TO THE HYDROXYL GROUP WHICH COMPRISES REACTING PHENOL AND AN OLEFIN IN LIQUID PHASE IN THE PRESENCE OF GAMMA-ALUMINUM OXIDE AS CATALYST, AND RECOVERING THE REACTION PRODUCT. 